Synthesis of the Antitumor Agent Aglycon (±)-Calicheamicinone Using an <i>o</i>-Quinone Monoketal Strategy
作者:Ian Churcher、David Hallett、Philip Magnus
DOI:10.1021/ja982125y
日期:1998.10.1
Commercially available 5-methoxysalicylic acid 16 was converted into the o-quinone monoketal 21, which was attached to the enediyne 22, resulting in 23. After protection of the tert-alcohol 24 and conversion of the ester 25 to aldehyde 28, treatment with LiN(TMS)2 gave a 1:4 mixture of the 12α- and 12β-ols 29 and 30, respectively. Oxidation of the mixture 29/30 followed by DIBAL-H reduction resulted
Synthesis and X-ray crystal structure of (?)-calicheamicinone
作者:Derrick L.J. Clive、Yunxin Bo、Natesan Selvakumar、Robert McDonald、Bernard D. Santarsiero
DOI:10.1016/s0040-4020(98)01140-5
日期:1999.3
Diels-Alder reaction between ketene acetal 3 and the beta-nitroacrylate ester 12 of (-)-8-phenylmenthol gave optically pure ketone 17. This substance was modified in such a way as to remove the chiral auxiliary and afford the epimeric silyl ethers 20M and 20m. Following procedures worked out using racemic materials, both 20M and 20m were converted into optically pure (-)-calicheamicinone (1). This is a crystalline substance, and an X-ray structure determination was carried out. (C) 1999 Elsevier Science Ltd. Ail rights reserved.